We already know that there is no jailbreak available for iOS 4.1 yet and OS 4.1 comes with a new 2.10.4 baseband that makes Ultrasn0w 1.1-1 to stop working on iPhone 4. So if you update to iOS 4.1 and then downgrade again to iOS 4.0.x by using SHSH blobs, you won’t be able to jailbreak because of the updated baseband. So right now if you want to keep you iPhone 4 jailbreakable after downgrading from iOS 4.1, you need to be on 1.59.00 baseband.

iphone-4-jailbreak-cydia-mywi-jailbreakme.com_-650x4871The following method lets you update to iOS 4.1 without updating the baseband.

  1. Close all background applications.
  2. Download the latest version of Tiny Umbrella http://thefirmwareumbrella.blogspot.com/
  3. Download the iOS 4.1 for iPhone 4 from here.
  4. Connect your iPhone 4, run Tiny Umbrella and click Start TSS Server button.
  5. When done, turn off your iPhone 4 and keep it connected to computer.
  6. Enter your device in DFU mode. To do this, hold power and home button together for exactly 10 seconds and then release the power button but keep holding home button until USB device is recognized.
  7. Run iTunes 10.
  8. If you see the restore logo, that means you have not entered the DFU mode. When you enter DFU mode, the following message appears on iTunes.
  9. Click OK and restore your device to iOS 4.1 by holding Shift Key (Windows) or Option Key (Mac), Clicking restore and browsing the downloaded iOS 4.1 firmware file.

[via ihackintosh, image via intomobile]